John Rockwell was the brother of film character actor Charles Trowbridge . He was a film actor for Columbia Studios and acted in film "westerns", predominately, but also worked for 'Republic Pictures Studios' for many years. He died at Glendale Sanitarium Hospital from 'hyperstatic shock' and 'enforced bed rest'. In other words, he had a 'nervous breakdown'. He also lived in the city of Glendale, California which is a suburb of Los Angeles, California.

Was a World War I veteran.His father, Charles Trowbridge, was originally from Decatur, Illinois and his mother, Katie Stephens, from Pachicca, Mexico. Jack was born in Vera Cruz, Mexico, as was his brother, Charles Trowbridge .His widow, Helen Trowbridge, died in 1976.He and his wife were interred in a vault at the Grandview Memorial Park, in Glendale, California.